Machining Applications Views: 44

Common problems with aluminum countersunk holes: welding, burrs and deformation. Practical tips: 1. Tool choice: cobalt HSS + TiAlN coated 3-flute countersinks with highly polished edges reduce aluminum welding; for higher demands, DLC diamond-like coating has an extremely low friction coefficient and the best anti-welding effect; 2. Parameters: high speed (2000-3000rpm) to stay out of the built-up-edge range; moderate feed (600-1200mm/min); cut in layers with a final pass of 0.1-0.2mm - never a zero cut (zero cutting causes friction and burrs); 3. Cooling: cutting fluid is a must - semi-synthetic or dedicated aluminum fluid recommended; cool generously with the nozzle aimed at the cut; kerosene also works well against welding; 4. Prevent deformation: support the back side on thin sheets to reduce vibration and distortion; optimize clamping with dedicated fixtures and even clamping force; cool thoroughly to lower workpiece temperature; let parts cool naturally before measuring; 5. Deburring: use dedicated deburring countersinks that chamfer and deburr in one pass; a final light reverse cut removes hole-edge burrs; 6. Notes: never use standard HSS on pure aluminum (1xxx series) - it welds badly; keep tools sharp (dull tools weld more); clean built-up edge off the tool regularly. Lihao Technology aluminum countersinks - cobalt HSS + TiAlN + polished edges - reduce welding by 80% and burrs by 70%.